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Azhdarchidae
Azhdarchidae (named after a dragon in Uzbek mythology, derived from the Persian Aži Dahāka) is a family of pterosaurs known primarily from the Late Cretaceous Period, and which included some of the largest known flying animals of all time. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the azhdarchinae to include the pterosaurs Azhdarcho, Quetzalcoatlus, and "Titanopteryx" (now known as Arambourgiania). The earliest azhdarchid fossils come from the Early Cretaceous of China and Brazil. However, there are controversial reports of Late Jurassic azhdarchids from Tanzania, Africa. Azhdarchid remains have mostly been found in fossil deposits in the Northern Hemisphere, with remains being sparce in the Southern Hemisphere, excluding finds in New Zealand and Australia. Azhdarchids differ from other forms of pterosaurs in several morphological aspects. Azhdarchids had straight, elongate jaws (2+ m) that were toothless, like many other derived pterosaurs. Instead of teeth, remains of foramina that lined the jaws indicate a horn-like sheath covering, akin to a beak. Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. It had been suggested azhdarchids were skimmers,Nesov, L. A. (1984). ["Upper Cretaceous pterosaurs and birds from Central Asia."] Paleontologicheskii Zhurnal, 1984(1), 47-57.Kellner, A. W. A., and Langston, W. (1996). "Cranial remains of Quetzalcoatlus (Pterosauria, Azhdarchidae) from Late Cretaceous sediments of Big Bend National Park, Texas." Journal of Vertebrate Paleontology, 16, 222-231. but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks.Chatterjee, S., and Templin, R. J. (2004). "Posture, locomotion, and paleoecology of pterosaurs." Geological Society of America Special Publication, 376, 1-64.Ősi, A., Weishampel, D.B., and Jianu, C.M. (2005). "First evidence of azhdarchid pterosaurs from the Late Cretaceous of Hungary." Acta Palaeontologica Polonica, 50(4): 777–787.Humphries, S., Bonser, R.H.C., Witton, M.P., and Martill, D.M. (2007). "Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method." PLoS Biology, 5'(8): e204.http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0002271 Systematics Azhdarchids were originally classified as close relatives of ''Pteranodon due to their long, toothless beaks. Others have suggested they were more closely related to the toothy Ctenochasmatids (which include filter-feeders like Ctenochasma and Pterodaustro). Currently it is widely agreed that azhdarchids were closely related to pterosaurs such as Tupuxuara and Tapejara. Taxonomy Classification after Unwin 2006, except where noted. * '''Family Azhdarchidae ** Aralazhdarcho''Averianov, A.O. (2007). "New records of azhdarchids (Pterosauria, Azhdarchidae) from the late Cretaceous of Russia, Kazakhstan, and Central Asia." ''Paleontological Journal, 41(2): 189-197. ** Arambourgiania ** Azhdarcho ** Bakonydraco ** Hatzegopteryx ** Montanazhdarcho ** Phosphatodraco ** Quetzalcoatlus ** Volgadraco ** Zhejiangopterus ** Possible valid azhdarchid genera *** Eoazhdarcho *** Doratorhynchus *** Bogolubovia *** Bennettazhia *** "Ornithocheirus" bunzeli References * Astibia, H., Buffetaut, E., Buscalioni, A.D., Cappetta, H., Corrall, C., Estes, R., Garcia-Garmilla, F., Jaeger, J.J., Jimenez-Fuentes, E., Loeuff, J. Le, Mazin, J.M., Orue-Etxebarria, X., Pereda-Suberbiola, J., Powell, J.E., Rage, J.C., Rodriguez-Lazaro, J., Sanz, J.L., and Tong, H. (1991). "The fossil vertebrates from Lafio (Basque Country, Spain); new evidence on the composition and affinities of the Late Cretaceous continental fauna of Europe." Terra Nova, 2': 460-466. * Bennett, S. C. (2000). "Pterosaur flight: the role of actinofibrils in wing function." ''Historical Biology, '''14: 255-284. * Nesov, L.A. (1990). reptiles of the Jurassic and Cretaceous of the USSR and the significance of their remains for the reconstruction of palaeogeographic conditions." Bulletin of Leningrad University, Series 7, Geology and Geography, 4'(28): 3-10 Russian. * Nesov, L.A. (1991). flying reptiles of the family Azhdarchidae: 11. Environment, sedirnentological conditions and preservation of remains." ''Bulletin of Leningrad Universitv Series 7, Geology and Geography, '''3(21), 16-24 Russian. Category:Azhdarchoids